Additive Manufacturing of Alumina-Based Ceramic Structures by Vat Photopolymerization: A Review of Strategies for Improving Shaping Accuracy and Properties.

Alumina is a polycrystalline oxide ceramic with different structures. Currently, α-alumina with a hexagonal close-packed stacking structure is mainly used for a variety of industrial applications. Alumina-based ceramics and composites have been widely used in various fields due to their excellent hardness, strength, creep resistance and good biocompatibility. However, it is difficult for Al2O3 ceramic components based on traditional preparation methods to meet the increasing industrial requirements, especially for applications such as precise multi-walled complex structures. Al2O3 ceramic additive manufacturing by vat photopolymerization 3D printing stands out owing to its ability to produce complex structures and tailored shaping accuracy/properties. The vat photopolymerization 3D printing of Al2O3 ceramics requires multiple steps including slurry preparation, photopolymerization shaping, debinding and sintering. Therefore, many efforts mainly focus on the strategies of optimizing the ceramic slurry formulation and the debinding/sintering process. This paper provides a scoping review to present optimization strategies for the above aspects of vat photopolymerization 3D printing, which creates a strong reference for researchers to improve the accuracy and properties of alumina parts. Finally, this review also states the main applications of Al2O3 ceramic components based on vat photopolymerization, and highlights the opportunities and challenges associated with this technology in the future. It is beneficial to understanding the future trends and policy directions of advanced manufacturing industry.